Progress on Brakes

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steve lapp
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Re: Progress on Brakes

Post by steve lapp »

Tom:

I don't know exactly what those seals look like, but is it possible you could source them from a hydraulic cylinder supplier? In rebuilding my rear Koni's, when Koni said a minimum of twelve weeks for the rebuild, I sourced piston rod pressure and wiper seals to replace the originals and rebuilt the shocks myself. (we shall see how well this works!). If you send me a detailed picture of the part, I might be tell you if I saw anything like it in my seal travels.

Cheers
Steve Lapp
Ontario Canada
2013 Nissan Leaf, 2002 Prius, 56 Healey 100-4, 74 BMW 2002, 330 GT 2+2 s/n 6241, 54 Dodge M152 (listed by decreasing fuel economy)
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Yale
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Re: Progress on Brakes

Post by Yale »

tyang wrote:
Yale wrote:
DWR46 wrote:i am sure there will be lots of EXPERTS who disagree with me, but I have used silicone fluid in non-ABS Ferraris since 1977 with zero problems. I do not take the sustem apart, just drain out the old fluid and put in the silicone. I then bleed a fair amount of silicone through to flush as much of the old fluid as is practical. I change the silicone every 10 years. Note that we do not use silicone in our vintage race cars, but for high performance street driving I am totally pleased. You will find lots of stories, but I have never had any problems that were related to the fluid. I have used it on both disc and drum braked cars.

Which exact brake fluid do you use. Apparently my car uses Castrol LMA which people seem to like and is synthetic but not DOT 5. So you are using what has been called a synthetic brake fluid that IS DOT 5?

Thanks Dyke.

Yale
I believe LMA is DOT 4. DOT 5 is specifically silicone brake fluid.

Tom
Yes Tom as I said Castrol LMA is not DOT 5 but DOT 4 BUT it IS synthetic, it is not petroleum based. However, it is not the same formula as a DOT 5 brake fluid. Best, Yale
Ex - 1964 330GT #6097
1963 Abarth Monomille
1970 Porsche 911S
1974 BMW 2002turbo
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Yale
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Re: Progress on Brakes

Post by Yale »

Ah yes "silicon" specifically not just generally synthetic. And now there is DOT 5.1 which is supposed to be compatible with DOT 4 and 3. Sorry for the wasted bandwidth. Y.
Ex - 1964 330GT #6097
1963 Abarth Monomille
1970 Porsche 911S
1974 BMW 2002turbo
250GT
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Re: Progress on Brakes

Post by 250GT »

Does not suprise me at all how Toms callipters look like.

When you using brass in moving parts (60% cupper) it will start oxidising

the pistons are probebly simple steel so you have got a galvano element, with voltage differance- the lower ranking principle.

The same happens when you are using brass buschings in you're front suspansion. despite graise, I showed fotos of this earlier in a post.(John V post ?)

I will look if I can find them( bushings).

Its only a hobby here.

Cornelis
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250GT
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Re: Progress on Brakes

Post by 250GT »

Lunch time here,
The only moving brass part in a Ferrari I know is the watervantilaor wheel in the water system.
here the promised fotos of drive train with brass bushings 50K km
lower almost new ones 10K km with the right pertinax bushings

Cornelis

I never overhauld my brake calipers you can buy them new cheap in GB org. Jaguar XK 150( Dunlop or Girling) about 100 euro each i think the last time I bought them,and hold another 30 years.
Drumbrake cars early Fiat 500 only 35 euro each.

Cornelis (without an u)
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klv
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Re: Progress on Brakes

Post by klv »

We've had quite a few problems with 'rebuilt' Dunlop calipers from early 105 series Alfas failing recently. Piston size seems to be very critical, as well as surface treatment, so check it all carefully when you get it back together Tom!

Cheers

Andrew
Kelly La Velle & Andrew Stevens
250GT
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Re: Progress on Brakes

Post by 250GT »

I would like to see the pistons too.
That are coming out of those heavy worn break housings.
thanks
C.
DWR46
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Re: Progress on Brakes

Post by DWR46 »

As to Synthetic vs. Silicone fluid. I have had excellent luck with Valvoline SYNTHETIC brake fluid and use it in all my non-silicone projects. I believe that Dow Corning used to be and stll may be the only supplier of SILICONE brake fluid, though I buy it under the Carquest brand.
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tyang
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Re: Progress on Brakes

Post by tyang »

250GT wrote:I would like to see the pistons too.
That are coming out of those heavy worn break housings.
thanks
C.
Hi Cornelis,

Here is a picture of a pair of pistons. The boots were removed for a better photo. I think they'll clean up well and I'll put a seal kit in when I get the bores resleeved.

Tom
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tyang
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Re: Progress on Brakes

Post by tyang »

steve lapp wrote:Tom:

I don't know exactly what those seals look like, but is it possible you could source them from a hydraulic cylinder supplier? In rebuilding my rear Koni's, when Koni said a minimum of twelve weeks for the rebuild, I sourced piston rod pressure and wiper seals to replace the originals and rebuilt the shocks myself. (we shall see how well this works!). If you send me a detailed picture of the part, I might be tell you if I saw anything like it in my seal travels.

Cheers
Hi Steve,

Here's a picture of the seals I'm looking for. The one on the right seals the post of the piston as it exits the the end of the equalizer. It fits inside the steel cup pictured behind it. The seal on the right is a doughnut shaped seal that fits on the piston.

Here are the dimensions:
32mm O.D. X 19mm I.D. and 6.5mm thick (pictured right)
30mm O.D. X 16mm I.D. and 5 mm thick (pictured left)

Thanks for looking.

Tom
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brake34.jpg
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'63 330 America #5053
365gtc/4
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Re: Progress on Brakes

Post by 365gtc/4 »

Hi Steve,
BTW, I'm striking out on the seals for the equalizer. T Rutlands sent me one seal, but it wasn't even close. The search continues, but I'm open to suggestions.
Tom
Tom
I do not know if this helps but I rebuilt my Koni levellers for a C4 with custom seals (Koni use an odd 21.75mm diameter shaft to force you to buy their seals. A bummer when they stop making replacement parts!!) Anyway I went to a hydraulic seal supplier who had a workshop with CNC mill/lathe. They made custom seals out of urethane. Probably can't make them out of rubber but worth talking to a suitable workshop. There are lots or materials and techniques available today to make small batches of custom stuff without too many $$$$.
Good Luck
John
John
Failure is not an option. It comes bundled with Windows.
steve lapp
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Re: Progress on Brakes

Post by steve lapp »

Hi Tom:

End of semester and sick, so just got to your posting. Well, there are lots of seals with 16 mm I.D., but not the 30 O.D. from what I looked at (Hercules and Parker). The 19 mm I.D. on the other is also not available.

But before we despair..would it be possible to bush the outside diameter of the 16 mm I.D. seal from say 24 to 30 mm? That is what I did for the Koni rebuild using the blue rod seal in the pictures. The orginal packing seals are to the left and are 16 mm I.D. and 28 I.D., and I bushed the outside of the 24 mm O.D. blue seal to fit the original bore of the Koni seal packing space ( I also added a wiper seal for dust, not shown). In redesigning the housing for the seal and bush, you need to make sure the seal material seals against any surface where the high pressure fluid could leak (i.e. at the rod/seal interface, and at the seal housing interface).

On the larger seal. Looking at your pictures of the various parts I am not clear on how the larger seal works, i.e. where there is hydraulic pressure and where there isn't, and what slides on what, so I don't know if a sleeve to an available size would work. However, if you are at the point where the seals are just not available and sleeving is last option, there is probably a way to do it.

On material compatability, the Parker Seals catalogue indicates EPDM is fine for DOT 4 fluids and polyurethane of their own spec (P5001 and P6000) are OK for silicone fluids. The polyurethanes do not seem to be good for DOT 4 according to Parker Seals.

The seals cost about $5 each!

cheers
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sized for web seals S6308162.JPG
sized for web seals S6308162.JPG (95.73 KiB) Viewed 11043 times
seals with 16 mm I.D. 24 O.D. x 5 thk
seals with 16 mm I.D. 24 O.D. x 5 thk
sized for web seals S6308161.JPG (97.83 KiB) Viewed 11043 times
Steve Lapp
Ontario Canada
2013 Nissan Leaf, 2002 Prius, 56 Healey 100-4, 74 BMW 2002, 330 GT 2+2 s/n 6241, 54 Dodge M152 (listed by decreasing fuel economy)
steve lapp
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Re: Progress on Brakes

Post by steve lapp »

forgot to mention the seal on the right is another type made of EPDM for the 16 mm rod, the blue one was thinner at 5 mm than the otehr at 6.5 mm and I need the room, so used the blue one.

cheers
Steve Lapp
Ontario Canada
2013 Nissan Leaf, 2002 Prius, 56 Healey 100-4, 74 BMW 2002, 330 GT 2+2 s/n 6241, 54 Dodge M152 (listed by decreasing fuel economy)
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tyang
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Re: Progress on Brakes

Post by tyang »

Hi Steve.

The large 32mm OD seal pictured on the left sits in a groove of the piston behind the spring.
Image
You can see the groove for the seal in the new piece:
Image
Pressure acts on it from the large side of the piston.
The second seal with the 30mm O.D. sits inside a cup with spring pressure behind it.

Tom
'63 330 America #5053
afwrench
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Re: Progress on Brakes

Post by afwrench »

I will happily submit to any flaming if I am wrong but I think the 3mm rod is designed to generate a bit of pull back on the piston in the brakes released position so the pads are off the disc.A bushing of sorts is inside the piston and the rod goes thru it. Minor flex of the thin metal leaves the bushing a bit behind and when the pressure is off the flex pulls the piston back.Mike
72,365gtc4,14681,2007 599 GTB
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